In this episode of "The Cost of Everything," host Christy Ai and professor Dr. Allan Zarembski delve into the essential role of metro systems in urban mobility. They highlight how these systems offer economical commuting compared to vehicle ownership, despite the significant costs involved in building subways. Factors like city size, complexity, and bureaucratic challenges contribute to these expenses, impacting funding for maintenance and expansion, particularly in areas with low population density outside major cities.